Perhaps you should try some spelling variations:
thien van » thi van
sach thu » sach thue, sach thieu, sach tham
thu mang » thu hang, thu bang, thu dang
hieu van » hieu va, lieu va, hieu ve
so sach » so sanh, bo sach, co sach
mang xa » lang xa, mang may, dang xay
cua tre » cua te, cuu tre, cua triet
bac va » ban va, bac ha, bao va
vi cua » vai cua, di cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach thu mang xa hoi. ((hieu van) OR (thien van)) cac ((bac va) or (duc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach thu mang xa hoi. ((hieu van) OR (thien van)) cac ((bac va) OR (duc va)) hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach thu mang xa hoi. ((hieu van) OR (thien van)) cac ((bac va) or (duc va)) hanh vi cua tre*".